Secondary test page: my CSS main page, where I use columns for the index. Individual entries should not be broken over two columns.

No

Possibly

No

Alternative and buggy

Alternative and buggy

Yes

-webkit-column-break-inside: avoid;
break-inside: avoid;

IE10 fails the test on the test page, but avoids breaks properly in the CSS main page. So it could be it supports this declaration. Investigating.

The WebKit-based browsers now break the paragraph at the last line instead of two lines earlier. Although this is allowed according to the spec (you should try to avoid breaks), I don’t see the point here, since the new effect is worse than the original.

By default, columns should be balanced if the height is too large (balance keyword). The auto keyword tells the browser to fill the height entirely and leave gaps at the end of the last column, if necessary.